The subject matter disclosed herein relates generally to turbomachine rotors having an abradable or abrasive patterned coating. More particularly, the subject matter disclosed herein relates to turbomachine rotors having abradable or abrasive pattern coatings applied over fluid-facing portions of the rotor, along with associated processes for applying such coatings.
Abrasive and/or abradable coatings have been applied to the surfaces of turbomachine rotors to increase the lifetime of the rotor's seal, and to further reduce radial clearances between components (e.g., rotor and stator components). Typically, metal or ceramic abradable seals are spray-coated onto the stationary seal surface, and are effective to establish a radial clearance of about 15 mils. While these coatings can be effective in reducing radial clearances, the coatings often fail to prevent undesirable flow patterns (e.g., swirls and/or tangential flows) at or near the rotating/stationary seal locations. These undesirable flow patterns can contribute to diminished turbomachine performance.